From 06e92afca89075628b12c9b4085b4cc7320081ac Mon Sep 17 00:00:00 2001 From: Jascha Sundaresan Date: Thu, 23 Oct 2025 03:07:41 +0400 Subject: nvmem: layouts: u-boot-env: add optional "env-size" property Some devices reserve a larger NVMEM region for the U-Boot environment than the actual environment data length used by U-Boot itself. The CRC32 in the U-Boot header is calculated over the smaller data length, causing CRC validation to fail when Linux reads the full partition. Allow an optional device tree property "env-size" to specify the environment data size to use for CRC computation. v2: add missing $ref line to DT binding Signed-off-by: Jascha Sundaresan Reviewed-by: Rob Herring (Arm) Signed-off-by: Srinivas Kandagatla --- Documentation/devicetree/bindings/nvmem/layouts/u-boot,env.yaml | 7 +++++++ drivers/nvmem/layouts/u-boot-env.c | 4 +++- 2 files changed, 10 insertions(+), 1 deletion(-) --- a/Documentation/devicetree/bindings/nvmem/layouts/u-boot,env.yaml +++ b/Documentation/devicetree/bindings/nvmem/layouts/u-boot,env.yaml @@ -46,6 +46,12 @@ properties: type: object description: Command to use for automatic booting + env-size: + description: + Size in bytes of the environment data used by U-Boot for CRC + calculation. If omitted, the full NVMEM region size is used. + $ref: /schemas/types.yaml#/definitions/uint32 + ethaddr: type: object description: Ethernet interfaces base MAC address. @@ -104,6 +110,7 @@ examples: partition-u-boot-env { compatible = "brcm,env"; + env-size = <0x20000>; ethaddr { }; --- a/drivers/nvmem/layouts/u-boot-env.c +++ b/drivers/nvmem/layouts/u-boot-env.c @@ -99,10 +99,12 @@ int u_boot_env_parse(struct device *dev, uint32_t crc32; uint32_t calc; uint8_t *buf; + u32 env_size; int bytes; int err; - dev_size = nvmem_dev_size(nvmem); + dev_size = device_property_read_u32(dev, "env-size", &env_size) ? + nvmem_dev_size(nvmem) : (size_t)env_size; buf = kzalloc(dev_size, GFP_KERNEL); if (!buf) {